Family: Taxodiaceae
Common Name: Japanese Cedar

This genus of conifers, comprised of only one species native to China and Japan, is best known by its numerous cultivars. The juvenile and dwarf cultivars are among the most attractive and reliable conifers for general garden use. The species is a tall, straight-trunked tree, with brown, fibrous bark, inward-curving leaves arranged spirally on the branchlets and small, roundish cones, about 2 cm (¾ in) in diameter. It is rarely grown outside its native area where it is cultivated for its timber.

Species

C. japonica, Japanese cedar, may reach over 40 m (130 ft) in height after very many years in its native Japan. It rarely exceeds 20 m (65 ft) in cultivation, forming a broad-based, pyramidal tree, which tapers into a long, narrow crown. The foliage of young trees is often quite dense but this becomes more open as the tree matures. It is dark green to olive in colour.

Popular cultivars include the very dwarf 'Compressa' which occasionally grows to 1 m (3 ft) with age. It is roundish in shape, generally with a short trunk visible at the base. The branchlets are very short and dense, and the leaves are short and prickly. In cooler areas, it colours a deep reddish bronze in winter.

'Elegans', the oldest and best known cultivar, may grow 4-5 m (13-16 ft) in 10 years and may eventually reach 8-10 m (26-33 ft). It has a broad, columnar or slightly conical growth habit. The foliage is of the juvenile type, but very different from the spiky, juvenile foliage of some of the dwarf cultivars. In spring and summer, it is a dull, slightly bronzy green, but in winter it changes to a deep plum colour, most pronounced in cooler climates. This cultivar is prone to storm damage as its branches are weak and brittle, so it is best grown among other trees or large shrubs.

Derived from 'Elegans' are the cultivars 'Elegans Aurea', with a more compact habit and yellow-green foliage, which does not change colour in winter, and 'Elegans Compacta', which grows to about 3 m (10 ft) tall and turns a bronze-brown in winter. 'Globosa Nana', the popular dwarf conifer, forms a dense, billowing mound of plain green, adult-type foliage which does not change colour. Although it generally reaches about 1 m (3 ft) or less in height, it may reach 2 m (6 ft) or more with age.

Cultivation

Cryptomerias are best suited to cool, moist climates and they do not grow well in areas of low rainfall or exposed coastal conditions. They like a sheltered position in partial shade or full sun. They do well in any reasonable garden soil, even appearing to tolerate slightly poor drainage. The taller forms often exhibit tufts of dead brown foliage, which should not be cause for alarm. Propagate the species from seed and the cultivars from cuttings, which seem to take root fairly easily.

Climate

Cryptomerias are suitable for zone 6.